Problem
The status of hardware features such as battery level and network connections must be able to be discovered by the user with no effort.
Solution
A bar is displayed along the top of every screen with a series of iconic representations of the status of the device. Common representations and placement of icons are used, so users can understand the key indicators on any device without familiarity with the specific device.
Variations
The Annunicator Row is present on all screens. It may only disappear or be of lower prominence when other controls disappear as for full-screen gameplay or video playback.
If the device operates very seamlessly, and has very reliable connectivity (or losses are generally not critical) and long battery life (ePaper devices, and plugged in items like some kiosks or CE devices) then the Annunciator Row may not be needed, and this may be solved with the Notification Area repurposed to display such information when it becomes critical instead. See that pattern for details on this functionality.
Interaction Details
Annunciators are notifiers, like lights and horns of the machine era. They are generally not something with direct interaction.
For touch and pen devices, it may be desirable to allow the user to select the Annunciator Row as a whole, in order to get more information, or to provide access to settings. This may also be accomplished by combining with the Notification Area.
Presentation Details
Items are displayed by icon only, whenever possible. Use words only when needed. Refer to my battery blog post about this iconic representation of info... DISPLAY STATUS! NOT JUST THERE, BUT THEY SAY SOMETHING...
Items are grouped by basic functionality. A conventional order has arisen, from left to right:
- Radios:
- Mobile networks.
WiFi.
- Bluetooth enabled, and activity or .
- IrDA or other non-wired networking as available.
- Access:
- Network activity.
- Network speed.
Message Waiting Indicator for voicemail, unless this is displayed by the Notification Area instead.
- Synch status or activity.
- Location services enabled. May or may not indicate when GPS is active.
- USB cable connected.
- Battery:
- Usually a single item, which changes based on charge level, and state (e.g. being charged)
- Those now rare devices with outboard (piggyback) or secondary batteries may display a second battery indicator.
The time of day (and sometimes the date) is also present, but may be in any of several places. The most common is centered, followed by right aligned.
Naturally, features not included with the device are not given space in the display. Some items may share space, and the highest priority feature or the one with the most important message is displayed.
Antipatterns
Don't let it change all the time. One layout, one size, one type of icon
Except when notifying of special conditions in places where the rest of the bar is suppressed (e.g. battery on a camera screen), do not pick and choose which items to show. Always show the same set in the same manner.